- Child adversity is known to increase risk of psychiatric problems, but at present there are few tools that can objectively measure whether or not a child has been exposed to such adversity
- Research across dentistry, anthropology and archaeology has shown that teeth preserve a permanent record of an individual's growth and physiologic exposures
- Building from this insight, this review paper proposes a framework for future research into the use of teeth as biomarkers of exposure to early-life adversity that might guide primary prevention efforts in psychiatry
Nearly half of all U.S. youth experience early-life adversity—such experiences include poverty, witnessing or experiencing violence or having a parent with mental illness. Exposure to adversity approximately doubles the risk of depression, anxiety and substance use disorders later in life.
Subscribe to the latest updates from Psychiatry Advances in Motion
It's thought that early adversity may harm the brain most during certain sensitive stages in development. However, these "windows of vulnerability" may also be "windows of opportunity" when exposure to prevention efforts could best reduce the long-term risk of psychiatric disorders.
The major obstacle to understanding these biological processes is the lack of tools to measure the presence and timing of early-life adversity. Patient self-report is susceptible to major biases in recall and self-disclosure, and health and social services records can substantially underestimate certain adversities.
Erin C. Dunn, ScD, MPH, a researcher with the Psychiatric and Neurodevelopmental Genetics Unit and the Center for Genomic Medicine at Massachusetts General Hospital, and colleagues propose that, on a population-wide scale, teeth could be used to help identify children and young adults who experienced adversity during sensitive periods in development. In Biological Psychiatry, they review relevant work in dentistry, anthropology and archaeology and propose a conceptual model for future research.
Teeth Record Early-Life Experiences
At least five properties make teeth promising potential biomarkers of exposure to early-life adversity:
- Teeth develop during sensitive periods — Primary teeth form between the fourth fetal month and age 3, permanent second molars form between age 3 and age 16, and permanent third molars ("wisdom teeth") are formed by age 18 to age 25. These time frames coincide with sensitive periods for brain development
- Teeth leave a permanent record of their formation — In the final stage of tooth development, proteins incrementally mineralize the dentin and enamel, two fundamental structures of the tooth. This process produces growth marks that remain visible in these structures, similar to the rings in a tree that mark its age
- Teeth preserve a record of physiologic stressors — Exposure to stressors such as poor nutrition and disease produce permanent structural defects or changes in the chemical composition of teeth. Moreover, growth marks known as stress lines record the timing of an individual's birth as well as the approximate week or even possibly the day in development when subsequent stressors occur
- Teeth may also preserve a record of psychosocial stressors — Four studies of nonhuman primates documented the emergence of stress lines potentially corresponding to psychosocial stressors such as separation from the mother, transfers to new enclosures and death of a sibling
- Primary teeth are spontaneously shed, and many adolescents have teeth extracted for orthodontia or have their wisdom teeth removed — Clinicians might one day send teeth to specialized labs for analysis and use the results to assess the risk of major depressive disorder and other psychiatric problems
The TEETH Conceptual Model
The authors have devised the TEETH (Teeth Encoding Experiences and Transforming Health) conceptual model, which has three main tenets:
- Early-life adversity may be associated with disrupted processes involved in brain and tooth development
- Developmental disruptions during tooth formation may produce time-resolved biological imprints that can be objectively captured
- Disrupted developmental processes may predict mental health risk
The authors list testable research hypotheses for the mental health field to investigate. They hope early, accurate identification of children at high risk will maximize the potential of primary prevention programs.
Learn more about the Psychiatric & Neurodevelopmental Genetics Unit
Learn more about Dr. Dunn's research